The synthesis of the title compounds started with the Vilsmeier reaction of (5b) and proceeded through the Wittig reaction with (R)-N-(methoxycarbonyl)-3-(triphenylphosphonio)alaninate (4), methylation with trimethylsilyldiazomethane, OsO4 oxidation, cyclocondensation with triphosgene, and catalytic hydrogenolysis. Chromatographic separation of the resulting diastereomeric mixture and subsequent deprotection
标题化合物的合成始于(5b)的Vilsmeier反应,并通过与(R)-N-(甲氧基羰基)-3-(
三苯基膦酰基)丙
氨酸的Wittig反应(4),三甲基甲
硅烷基
重氮甲烷甲基化,OsO 4氧化,用
三光气进行环缩合和催化氢解。色谱分离得到的非对映异构体混合物,然后进行脱保护,首次获得了两个所需的核苷[[R-(R ∗,S ∗)]-和]。